1. Field of the Invention
This invention relates to moisture barrier fabrics and to methods for making them. The fabrics are suitable, e.g., as upholstery fabrics.
2. Description of Related Art
The need for fabric materials that are impervious, or at least resistant, to moisture has long been recognized in the upholstery industry. The desirability of preventing the penetration of liquids into household furniture is apparent to anyone with small children. Penetration of moisture into the interior of furniture can result in odors and decay of the internal parts of the furniture. In addition, fabrics for use in outdoor furniture are also desirably moisture resistant, since these fabrics are frequently exposed to the elements. Window treatment fabrics, by virtue of their placement near windows and doors, are often exposed to moisture as well.
Moisture barrier fabrics that are composite materials having a fabric “face cloth” and a latex backing layer are known in the art. The latex is typically applied in one or more coats, using a doctor blade or other device for applying a thin coating. Prior to application of the latex coating, however, composite moisture barrier fabrics have generally required treatment with a primer to prepare the fabric surface to receive the backing. This ensures good bonding between the fabric and the backing, and reduces the risk of delamination or separation. However, use of a primer requires an additional coating step and the requisite coating process equipment and the application of additional chemicals to the fabric.
Many of the latices used as fabric coatings have relatively high curing temperatures. This limits the type of fabric that can be used in making the face cloth to those that have melting points well above the curing temperature of the latex. Often, a latex is used that has a curing temperature in excess of 300° F., which would turn a woven polypropylene fabric into a puddle of resin. This effectively removes polypropylene from consideration as a possible facecloth material.
Typically, the face cloth materials of the moisture barrier fabrics are treated with fluorochemicals to increase oil and water repellency. This treatment generally includes applying the fluorochemicals, e.g., by spraying or other methods, to the face cloth prior to assembly into the composite, or during application of the backing layer to form the composite. However, such application does not provide a complete coating of the backing layer, or even provide complete coverage of the face cloth, and small openings through which moisture can penetrate the fabric remain. In addition, subsequent processing of the fabric can damage the repellent coating.
Many moisture barrier fabrics have poor tactile qualities, and do not have a pleasant “hand.” Since these fabrics are often used as upholstery fabrics for interior use where the consumer will often touch the fabric, the heretofore necessary trade-off between moisture barrier performance and the feel of the fabric to the touch has resulted in some consumer dissatisfaction.
There remains a need in the art for a moisture barrier fabric that can be prepared using low coating/curing temperatures, that has improved repellency, that has good hand without sacrificing moisture barrier performance, and that does not require the use of a primer for good results.